Screen for centrifugal baskets



March 17, 1925. 1,530,019

R. A. STEPS SCREEN FOR CENTRIFUGAL BASKETS Filed March 3 0, 1925 I 11vENTOR Patented Mar. 17, 1925.

UNITED STATES PATENT. FFICE.

ROBERT ALEXANDER STEPS, OF LOS ANGELES, CALIFORNIA.

SCREEN OENTRIFUGAL BASKETS.

Application med March so, 1923. Se ial No. czssaa.

To all whom it may concern:

Be it known that 1, ROBERT ALEXANDER Srnrs, a citizen of the UnitedStates, residing at Los Angeles, in the county of Los Angeles and Stateof California, have in vented a new and useful Screen for CentrifugalBaskets, of which the following is a a specification.

This invention relates to screens such as are used in centrifugalbaskets, and which are formed of a foraminous sheet bent into asubstantiallycylindrical shape, the twoabutting edges being then more orless fastened together in some suitable manner.

Heretofore there have been various ways of fastening these edges, butfor several reasons none. of these modes of fastening have beenaltogether satisfactory.

As is well understood the material such as sugar, for instance, which istreated in these centrifugal baskets, 1s finally d1s-.

charged therefrom by means of a discharging shoe, the sharp tip or pointof which presses on the screen as the latter revolves with the basketslowly, during the discharging operation, thereby cutting the sugar orother material off the screen and d1scharging it through the bottom ofthe basket in a .well known manner.

As the discharging proceeds this shoe is gradually lowered along thescreen by mechanical means, until all the material is presentlydischarged by the ac tion of this descending shoe scraping on the slowlyrevolving screen and basket.

Owing to this scraping action which the discharging shoe necessarily hason the screen, the mode in which the aforesaid abutting edges of thelatter are oined together, must comply with some rather rigorousconditions which have not been well complied with in any of the jointsheretofore proposed. In the first place the joint should be as fiat aspossible, i. e., it should not be bunchy as occurs when the character ofthe joint involves too many layers of the sheet in making it, asthelatter produces a I only poorly solved could be cut or encountered bythe relative" circumferential movement between the joint and the shoe.It'i-s true that screens heretofore proposed have no edges thatencounter the shoe in the circumferential direction, but most of themhave'upstanding edges that freely encounter and out against the shoe inits downward direction, and since thelatter is fully as important as theformer, it is clear that the screens so proposed have the problem whichcon fronted them.

' By a novel combination and rearrangement which I will now describe, myinvention has the double advantage of getting away from theobjectionably thick bunchy joints that have heretofore been known, andat the same time getting away from any upstanding edge that couldencounter the discharging shoe either in its relative down ward orcircumferential movement, and

whilesecuring these extremely important advantages my invention furtherresults in the very simplest possible kind of a joint, and perfectlysatisfies all operating conditions or difficulties that could beencountered.

In the drawings Fig. 1 illustrates the foraminous sheet flattened out,part of the sheet being broken away for space economy. Fig. 2 is anenlarged View showing the two edges to be joined. Fig. 3 is a similarview after the edges are joined. Fig. 4 is a plan view looking down onthe joint. Fig. 5 shows the foraminous sheet bent into cylindrical shapeand joined, the dischargershoe being indicated more or lessdiagrammatically in its relation to the screen. Fig. (i is a more orless diagrammatic view showing the discharging shoe cutting the sugar orother ma terial off the screen. F ig; 7 shows the edges about tobejoined, but in this case illustrating a modified form of my invention.Fig. 8

shows the joint when completed in accordance with the modification shownin Fig. 7.

'In Fig. 3 the metal on one side of the joint has been shaded by lighthorizontal lines, while the metal on the other side of the joint hasbeen shaded by light linesrunning at an angle, as it is thought thatthis shading will more clearly point out the limits of the metal andalso the character of thejoint when completed.

Also it will be understood that the sheet shown in these drawings isperforated by a great number of very fine holes so it can act like ascreen permitting the liquid to pass through same, but retaining .thesolid material, such as sugar crystals, inside the screen during thecentrifuging treatment. These perforations have been partially indicatedin Fig. 1, but have been omitted from all other figures in the interestof clear-ness and simplification.

In equipping this screen or foraininous sheet with my new joint it isonly necessary to slit the one edge 13 into a series of substantlallyhorizontal tongues b, the same being practically contiguous with eachother,

and to form near the other edge A a slot a for each of the tongues 6,these slots a being slanted with reference to a vertical direction.

Broadly speaking there was of course no invention in merely usingtongues along the one edge and some sort of slots along the other edge,as tongues and slots are an extremely old and primitive fasteningexpedient wherever it is desired to more or less join together twooverlapping surfaces, but by the particular idea of'slanting the slots ain the manner indicated I have brought forth a joint that has a new andparticularly useful advantage in connection with these centrifugalscreens.

As indicated in Figs. 2, 3, and. 1, each of the tongues Z) needmerely bepushed through the slanted slot ct provided for it and the joint iscomplete, and has the appearance shown in Figs. 3 and at. In doing thisthe tongues are inserted through the slots from the inside of thecylinder outwardly, which leaves the inside where the sugar and othermaterial is accumulated. practically smooth as the tongues are all onthe outside of the,

bunchy on account of the several thicknesses of metal which thisinterweaving of the edges gives, which is rendered more-objectionable inview of the tendency of the metal to resist flattening or smoothing outof the oppositely directed curvatures which this interweaving actionproduces on the tongues.

My tongues however receive no such opposite curvatures in respect toeach other, as they are all treated alike. and are merely pushedstraight through the opposite slots, which involves no interweavingaction and consequently results in a very flat thin oint that can beeasily smoothed out to a condition of no appreciable thickness overthesingle layer of metal on either side of the joint. In fact it ispractically unnecessary to attempt any such smoothing, as neither thetongues on the one side, nor the edge with the slots .on the other side,are bent in making the connection, with the result that the joint is notaccompanied with the bunchiness that characterizes other joints.

1 will now describe the excellent manner in which this joint is adaptedto co-operate with the dischargin shoe.

Figs. 5 and 6 indicate the discharging shoe at 0, and as is well knownthe sharp tip or edge of this shoe is pressed against .the screen by theimpact of the sugar wall d, as the sugar revolves with the screen andbasket in direction of arrow 1 and encounters the shoe 0 which ismechanically held in the approximate position shown in Fig. 6.

As the sugar is cut out from the upper portion of the basket, the shoeis mechanically lowered to continue the cutting action, this loweringbeing accomplished by well known mechanisms known as dischargers whichneed not be described here as they have no special connection with thisinvention.

Fig. 5 however, by means of arrow 1, indicates the circumferentialrotation of the screen, and by means of arrow 2 indicates arrow 3 ismore or less variable also, but

the fact that it is inclined somewhat as indicated in Fig. 5 is obviousfrom the conditions mentioned.

lVith this established, attention is now directed to Fig. 3 which showsthe joint on a suiiiciently large scale so that the action of hedischarging tip in passing over it can be bestunderstood. Arrow 3,though probably excessively inclined, is applied to this figure toindicate the course of the discharging shoe over the joint.

' As the sharp tip of the shoe moves along the arrow 3 it will be seennever to encounter an upstanding edge. as all the edges encountered runfrom higher surfaces on to lower surfaces. which is the ideal condition,as no tearing or cutting of any sort can then occur between the screenat the joint-and the sharp tip of the discharger as it moves over it.Taking any particular slot and tongue in Fig. 3, it will be seen that amember moving approximately in direction of arrow 3 will run off themetal a on to tongue I), and again off the metal I) at the lower edge ofthe tongue on to the metal a, and in due course again off the metal a;of the next lower slot on to the tongue 1) adjacent thereto, and in eachof these cases the motion was always from a higher surface to a lowersurface which illustrates the point I am making that no upstanding edgeis encountered in passing over my joint in a downward direction, or inone circumferential direction, or in any resultant direction comprisinga combination of these two. From what has already been stated it isclear that this is the ideal arrangement in view of the clownward andcrosswise direction in which the discharging shoe actually traverses thejoint.

In conclusion, it may be fairly stated that the advantages hereinbeforestated, i. e., the advantage of an unusually thin fiat joint, and alsothe advantage of unusually good adaptation to the passage of thedischarger shoe over the joint, are both obtained largely by my idea ofslanting the slot-s with reference to a vertical direction, andproviding such a slot for practically every tongue.

Of course my invention can be applied with more or less modification asillustrated in Figs. 7 and 8, which has the advantage of making theslotted edge a little stronger, and no doubt no serious difficulty wouldbe encountered if any one endeavored to apply my invention by makingsmall modifications such as omitting a small number of the tongues, orperhaps a small number of the slots, or perhaps by failing to insert asmall number of the tongues in the slots, but in the main the form whichI have illustrated and described is the best mode in which I prefer tomake and apply this invention.

I claim.

1. A centrifugal screen comprising a foraminous sheet adapted to be bentsubstantially into a cylinder, the edges of said foraminous sheet beingheld together by tongues formed along one edge, and by slots formedadjacent the other edge, the slots being slanted with reference to theaxis of said cylinder.

2. A centrifugal screen comprising a foraminous sheet adapted to be bentsubstantially into a cylinder, the edges of said foraminous sheet beingheld together by tongues formed along one edge, and slots formed nearthe other edge, the slots being slanted with reference to a verticaldirection, and the tongues being inserted through said slanted slotsfrom the inside of the foraminous cylinder outwardly so as to leave theinside of the cylinderv substantially smooth.

3. A centrifugal screen comprising a foraminous sheet adapted to be bentsubstantially into a cylinder, the edges of said foraminous sheet beingheld together by tongues formed along one edge, and slanted slots nearthe other edge, the tongues being substantially contiguous to each otherand formed by slits extending substantially horizontally along the metalsheet, and said slots being slanted with reference to a verticaldirection. substantially all the tongues being inserted through saidslanted slots from the inside of the cylinder outwardly so as to leavethe inside of the cylinder substantially smooth.

4. A centrifugal screen comprising a foraminous sheet adapted to be bentinto a cylinder, the edges of said sheet being held together by tongueson the one edge and slanted slots on the other edge, there being a slotfor substantially every tongue, the said slots being slanted withreference to a vertical direction, and substantially all the tonguesbeing inserted through said slanted slots from the inside of thecylinder outwardly so as to leave the inside of the cylindersubstantially smooth.

5. A centrifugal screen comprising a foraminous sheet adapted to be bentsubstantially into a cylinder, one edge of said sheet being slit into aseries of substantially horizontal contiguous tongues, and the oppositeedge of said sheet having a slot for each of said tongues, the saidslots and tongues being adapted to form a joint, the said slots beingslanted with reference to a normal vertical direction, and each tonguebeing passed through one of said slanted slots from the inside of thecylinder outwardly so as to leave no upstanding edge that could impede amovement in a downward direction or in one circumferential directionacross the joint.

Signed at Denver, in the county of Denver and State of Colorado, this26th day of March, 1923.

ROBERT ALEXANDER STEPS.

